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What does the "Reset ATS Controller" command accomplish on a Next Gen Rack Automatic Transfer Switch (ATS)?

Issue

What does the "Reset ATS Controller" command accomplish on a Next Gen Rack Automatic Transfer Switch (ATS)?

Product Line

Rack Power Distribution - Automatic Transfer Switch

AP7721

AP7722A

AP7723

AP7724

AP7730

AP7731

AP7732

AP7752

AP7753

AP7750A

Environment

All serial numbers

All firmware versions

Cause

This information is provided to users wishing to understand what the "Reset ATS Controller" command does and the functions it performs. Please review below.

Resolution

Please Note: Executing this command will cause the ATS output to turn off for 330-340ms. The ATS is resetting and the CPU/microcontroller is not in control and able to maintain the output. (This command also effectively gets issued when the user issues a "Reset to Defaults" command via the onboard Network Management Card.)

There are a couple of scenarios that will have different reactions after you perform the function of resetting the ATS controller through the Network Management Card interface, or the ATS Serial port interface.

Resetting the ATS controller will cause the ATS to switch back to Source A regardless of the ATS preference settings. So how does this affect the ATS?

If the ATS is set for no (none) source preference and source B is the currently selected source. When you reset the ATS controller, the ATS will switch to source A and remain on source A. Why? Source A is the default source selection and as long as Source A is acceptable, and the preference is set for none, there is no reason for the ATS to switch back to source B.

If the ATS is set for source B as the preferred source and source B is the currently selected source. When you reset the ATS controller, the ATS will switch to source A and approximately 30 seconds later switch back to source B Why? Source A is the default source selection. But with source B as the preferred source, the ATS will switch to source A during the reset command, and then wait to make sure source B is acceptable, and then switch back to source B. That process should take about 30 seconds.

Lastly, scenarios one and two also cover how the ATS powers up when a coldstart is performed.